Disconnecting Dynamics 365 Items
Sometimes you may want to "disconnect" an Entity or Field from Microsoft Dynamics 365 so that changes to its value do not update the database. This is useful, for example, if you are using a Microsoft Dynamics 365 Field for an interim calculation but don't want that value to get written to the database.
To disconnect an item, right-click it in the Entities view and select Disconnect Item. Alternatively, with the item selected, click the Disconnect Item button on the DYNAMICS ribbon.

Confirming the Disconnection
The Schema Source section of a Field definition indicates where the Entity or Field originated. For a Microsoft Dynamics 365 Field, this would look something like this.
After you disconnect the Field, the Schema Source will simply say "internal," such as for any Field you added using irAuthor.